Injection device

ABSTRACT

The invention features an injection device for injecting a liquid or semi-solid composition into a subject.

This application is a continuation of Ser. No. 08/777,634 filed Dec. 31,1996 now U.S. Pat. No. 5,776,107.

BACKGROUND OF THE INVENTION

The invention relates to a device for the parenteral administrationthrough a needle of liquid or semi-solid drug compositions wherein theneedle is protected before and after the injection.

The parenteral introduction of pharmaceutically active compounds ispreferred over oral dosage for many indications, e.g., where the drug tobe administered would partially or totally degrade in thegastrointestinal tract, or where there is need for a rapid biologicalresponse. The need for extemporaneous preparation of such parenteralcompositions is eliminated, or simplified, by the use of pre-filledadministration devices in which the liquid to be injected is pre-loadedinto the device (e.g., a pre-loaded syringe). Such pre-loaded devices,however, have a number of drawbacks, including the inability to preservethe asepsis or sterility of the needle, as well as the general danger ofusing an exposed needle. To eliminate these drawbacks, it is necessaryto avoid the direct exposure of the needle with the environment bothprior to and following injection.

SUMMARY OF THE INVENTION

The invention features a comparatively inexpensive injection device witha needle for parenteral injection of liquid or semi-solid drugcompositions into a subject, e.g., a mammal such as a human, wherein theneedle is protected both before and after the injection.

In general, the invention features an injection device including ahousing, the housing having proximal and distal ends and designed tocontain a liquid or semi-solid drug composition; a hollow needle, theneedle affixed to the distal end of the housing and extendinglongitudinally within the housing; a plunger, the plunger arranged toslide within the proximal end of the housing; and a hollow sleeve, thehollow sleeve arranged to cover the needle prior to injection andarranged to retract into the housing during injection; wherein thedevice is designed such that when the sleeve is pressed against thesubject, the sleeve retracts into the housing thereby allowing theneedle to penetrate the subject, and when the plunger is forced furtherinto the housing, the drug composition is forced from the housingthrough the needle and into the subject.

In one embodiment, the device is further designed such that when thedrug composition is forced from the housing, the plunger forces thesleeve out of the housing to cover the needle. In a further embodiment,the housing contains the liquid or semi-solid drug composition.

In another embodiment, the device further comprises a septum plunger,the septum plunger slidably arranged within the housing between theplunger and the distal end of the housing. In a further embodiment, thedevice is further designed such that when the drug composition is forcedfrom the housing, the plunger forces the septum plunger into the sleeve,and the septum plunger forces the sleeve out of the housing to cover theneedle. In still a further embodiment, the housing contains the liquidor semi-solid drug composition between the plunger and the septumplunger.

In still another embodiment, the housing contains a liquid and a drydrug composition, where the device is designed to combine the liquid andthe dry drug composition prior to injection.

The device can further include a releasable lock to inhibit the movementof the plunger into the housing. The device can also include a removablecap which covers the sleeve. The proximal end of the housing may have aflange and the plunger may also have a flange.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, the preferred methods andmaterials are described below. All publications, patent applications,patents, and other references mentioned herein are incorporated byreference in their entirety. In case of conflict, the presentspecification, including definitions, will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting.

Other features and advantages of the invention will be apparent from thefollowing detailed description, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of an injection device prior touse.

FIG. 2 is a partial cross-sectional view of the injection device of FIG.1 during use.

FIG. 3 is a partial cross-sectional view of the device with the needleinjected into a subject.

FIG. 4 is a partial cross-sectional view of the injection device beingwithdrawn from the subject with a drug composition remaining in thesubject.

FIG. 5 is a partial cross-sectional view of the injection devicefollowing complete withdrawal of the needle from the subject.

FIG. 6 is a cross-section of the injection device through line 6—6 inFIG. 1.

FIG. 7 is a view of the sleeve of the injection device.

DETAILED DESCRIPTION

It is believed that one skilled in the art can, based on the descriptionherein, utilize the present invention to its fullest extent. Thefollowing specific embodiments are, therefore, to be construed as merelyillustrative, and not limiting.

FIG. 1 shows injection device 1 including housing 10, having a proximalend and a distal end 14 a, 14 b. The distal end of housing 10 has twoholes 40 a and 40 b partially separating the two parts 14 a and 14 b ofthe distal end (as best seen in FIG. 6). Needle 12 is attached to part14 a of the distal end. The housing 10 can be made from a rigid materialsuch as glass, plastic, or metal. The needle 12 is hollow anddouble-ended, wherein its distal end, remaining outside housing 10, hasa point capable of piercing the skin of a subject, and its proximal end,remaining within housing 10, is capable of piercing septum plunger 16.On the proximal end of housing 10 is a flange 28 to assist in removal ofdevice 1 from the subject following injection.

An sleeve 22 surrounds needle 12 so that needle 12 is not fully exposedto the environment until used. Sleeve 22 has longitudinal slots 45 a and45 b along its length (see FIG. 7; slot 45 b is on the back of thesleeve and is thus not shown). The two parts 14 a and 14 b of the distalend are joined by radially extending connecting members 42 a and 42 b(see FIG. 6). Connecting members 42 a and 42 b, respectively, slidethrough slots 45 a and 45 b in sleeve 22, while sleeve 22 slides throughholes 40 a and 40 b in housing 10. Sleeve 22 can be made of suitablyrigid material, such as metal, glass, or plastic. Seal 24 covers theopening 23 of sleeve 22 to maintain the sterility of needle 12 andprevent sleeve 22 from unintentionally retracting into housing 10through holes 40 a and 40 b prior to injection.

Seal 24 can be made of a thin material, such as plastic or wax, which iseasily penetrated by needle 12 during injection. A similar seal can alsocover slots 45 a and 45 b in sleeve 22, to further protect the sterilityof needle 12.

Septum plunger 16, contained within housing 10, includes a bore 26, inwhich needle 12 rests prior to subsequently piercing septum plunger 16.A liquid or semi-solid composition 20 is isolated in housing 10 betweenthe septum plunger 16 and the plunger tip 30, attached to plunger 29.Septum plunger 16 and plunger tip 30 may be made of non-rigid, solidmaterial such as rubber, which allows septum plunger 16 and plunger tip30 to slide within housing 10 but still maintain sufficient frictionwith the inner sides of housing 10 to seal composition 20 within housing10.

The proximal end of plunger 29 has a thumb flange 18 to assist in thedepression of plunger 29 into housing 10, and the distal end of plunger29 has a longitudinal bore 27 to receive needle 12 following injectionof composition 20 out and through needle 12. Plunger 29 can be made froma rigid material, such as metal or plastic. A removable lock 25 may beplaced between flange 18 and flange 28 to inhibit the further depressionof plunger 29 into housing 10 after activation of device 1, i.e., afterthe housing 10 is filled with a drug composition and the proximal end ofthe needle is pierced through septum plunger 16. A removable cap 21 canalso be used to protect both needle 12 and sleeve 22 prior to use. Bothcap 21 and lock 25 can be made from suitable rigid material such asplastic, metal, or rubber.

FIG. 2 shows device 1 wherein plunger 29 has been pressed into housing10 to activate device 1 as follows. When plunger 29 is depressed,plunger tip 30, composition 20, and septum plunger 16 are displacedtoward the distal end of housing 10. Septum plunger 16 is pierced atbore 26 by needle 12. As a result, the proximal end of needle 12 isexposed to composition 20. Device 1 is now in an activated state. Lock25, by contacting both flange 18 and flange 28, inhibits the furtherdisplacement of composition 20 from housing 10 through needle 12following activation of device 1, i.e., composition 20 is allowed tofill needle 10, but lock 25 inhibits significant release of composition20 through needle 10.

FIG. 3 shows device 1 wherein needle 12 has penetrated skin 32 of thesubject being treated. As device 1 is pressed against skin 32, sleeve 22is retracted into housing 10, through holes 40 a and 40 b, by the forceof pressure against skin 32. Needle 12 passes through sleeve 22 atopening 23. As shown, needle 12 has penetrated through skin 32 into thesubcutaneous layer 34.

FIG. 4 shows device 1 wherein lock 25 has been removed and plunger 29has been depressed which moves plunger tip 30 toward septum plunger 16,thereby injecting composition 20 into subcutaneous layer 34 throughneedle 12. Once composition 20 has been injected and plunger tip 30rests against septum plunger 16, housing 10 is moved away from skin 32by exerting pressure against the lower part of the flange 28 whilesimultaneously exerting opposing pressure on flange 18 of plunger 29.This relative movement of the plunger 29 and housing 10 causes plungertip 30 to force septum plunger 16 against sleeve 22 as both plunger tip30 and septum plunger 16 slide toward parts 14 a and 14 b of the distalend of housing 10, which in turn forces sleeve 22 out of housing 10through holes 40 a and 40 b. As plunger tip 30 and septum plunger 16 aremoved toward distal end of housing 10, needle 12 penetrates septumplunger 16, plunger tip 30, and enters bore 27 in plunger 29.

FIG. 5 shows needle 12 fully withdrawn from skin 32 and sleeve 22 fullycovering needle 12. Composition 20 remains in the subcutaneous layer ofthe patient. As can also be seen in FIG. 5, the proximal end of needle12 has been pushed through septum plunger 16 and plunger tip 30 andremains in bore 27 of plunger 29.

FIG. 6 is a cross-sectional view of FIG. 1 at 6—6. FIG. 6 shows holes 40a and 40 b in housing 10. Radially extending connecting members 42 a and42 b extend through slots 45 a and 45 b, respectively, to connect parts14 a and 14 b of the distal end. Needle 12 is fixed to central part 14 aof the distal end, and sleeve 22 can slide through holes 40 a and 40 b.FIG. 7 shows an isolated sleeve 22 having slots 45 a and 45 b (45 b isnot shown but positioned directly opposite to slot 45 a on the otherside of sleeve 22) and opening 23. Radially extending connecting members42 a and 42 b, respectively, slide through slots 45 a and 45 b.

Composition 20 is a liquid or a viscous semi-solid compositioncontaining a drug. The drug of composition 20 can be any drug capable ofbeing parenterally administered as a liquid or a semi-solid. Forexample, the drug can be a vaccine, a peptide, a protein, or a smallchemical entity. Examples of suitable drugs include insulin and heparin.For drugs which are not stable in liquids over an extended period oftime, the liquid and the dry drug can be stored in separate chamberswithin housing 10. The device can be designed such that the liquid andthe dry drug are combined together just prior to injection.

For example, the chamber created between septum plunger 16 and plungertip 30 (e.g., in FIG. 1) in housing 10 can be separated into twoseparate parts by a fixed wall or film that can be punctured, e.g., bypressure of the plunger 29 on the plunger tip 30, or a puncturing means.Alternatively, the two parts of the chamber can be separated by a movingwall or septum. In this case, the top or proximal part of the chamberabove the moving septum contains the liquid portion of the composition,and the distal part of the chamber contains the solid, e.g., powder,portion of the composition. When plunger 29 is pushed down, it appliespressure to the plunger tip 30, which applies pressure to the liquidportion of the composition. This, in turn, applies pressure on themoving septum, causing it to move in a distal direction. The housing isdesigned with a liquid bypass (e.g., a bulge or passage in the housingwall) in a location that initially prevents passage of liquid from onepart of the chamber to the other, but when the moving septum reaches aspecific location, the bypass allows the liquid to pass from the toppart of the chamber into the lower or proximal part of the chamber onthe other side of the moving septum.

To maintain sterility, the device of the invention can be stored in aconventional blister pack prior to use.

OTHER EMBODIMENTS

It is to be understood that while the invention has been described inconjunction with the detailed description thereof, that the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the claims.

What is claimed is:
 1. An injection device for injecting a liquid orsemi-solid composition into a subject, the device comprising: a hollowhousing having a proximal end and distal end, said housing beingconfigured to contain a liquid or semi-solid composition; a hollowneedle, said needle affixed to the distal end of the housing andextending longitudinally within said housing; a plunger arranged toslide within the proximal end of the housing; and a hollow sleeveslidably connected to the distal end of the housing and arranged tocover the needle prior to injection and to retract into the housingduring injection; wherein the device is configured such that when thesleeve is pressed against the subject, the sleeve retracts into thehousing thereby allowing the needle to penetrate into the subject, andwhen the plunger is pushed into the housing, the composition is pushedfrom the housing through the needle and into the subject.
 2. Aninjection device of claim 1, wherein the device is further configuredsuch that when the composition is pushed out of the housing, the plungermoves the sleeve out of the housing to cover the needle.
 3. A device ofclaim 1, wherein the housing contains the liquid or semi-solidcomposition.
 4. A device of claim 2, wherein the housing contains theliquid or semi-solid composition.
 5. A device of claim 1, wherein thedevice further comprises a releasable lock to inhibit movement of theplunger into the housing.
 6. A device of claim 1, wherein the devicecomprises a removable cap which covers the sleeve.
 7. A device of claim1, wherein the proximal end of the housing comprises a flange.
 8. Adevice of claim 1, wherein the plunger comprises a flange.